High throughput microsatellite analysis identifies tumor-specific genetic alterations associated with bladder cancer progression. The proposed work seeks to explore several clinical issues related to bladder cancer managed based on the detection of these genetic changes in primary tumors and urine. The specific aims of this project are: (1) to define the sensitivity and specificity of microsatellite marker panels for the detection of recurrent superficial bladder cancers and, (2) to preliminarily explore whether specific patterns for microsatellite alterations (i.e., LOH or instability) correlate with increased risk of disease recurrence or progression in both superficial and invasive cancers. These specific aims will be accomplished through prospective microsatellite analysis of paired tumor and urine specimens obtained from patients with superficial and invasive bladder cancers undergoing therapy with curative intent at the John Hopkins Hospital. The analyses will be performed using molecular methods and technology developed in projects #1 and 2. The larger goal of this project is to lay a practical foundation for future studies of microsatellite analysis for monitoring and for the establishment of risk profiles for patients with different stages of bladder cancer.